Originally Posted by hatzie (Post 8752388)

...Snip...

When I convert over to the Sanden style compressor I run the ground through the High Pressure Cutout Switch and leave the LPCO in the hot as originally wired. You can run the HPCO in series with the LPCO but it's easier to put it in the ground side.

Originally Posted by swissarmychainsaw (Post 8752428)

Thanks for this.
I just reached out to the supplier of my parts:

The modern compressor do not have any switches in them, so it is recommended to install one. Here is a link to a very easy to install switch kit.

https://www.originalair.com/ac-high-...tch-kit-o-ring

In your situation, it would need to be attached to the lower fitting of the condenser (#6) and then attach the hose directly to that.

Just ordered this, but I don't think it will get here in time for my vacation plans!

Originally Posted by hatzie (Post 8752446)

You could get a crimp in pressure switch fitting and install in the hose right off the compressor head.

The compressor head fittings, be it a Sanden or one of the Harrison units, can be acquired with an HPCO threaded switch fitting... and even both LPCO & HPCO threaded switch fittings.

Originally Posted by hatzie (Post 8747808)

Let us know how the Mastercool Hydracrimp knockoff works.

Originally Posted by hatzie (Post 8543024)

Looks like you have a compressor cycling thermal cutoff switch with a capillary tube in the Evaporator. There should be a Low pressure cutoff switch on the accumulator as well. The aftermarket compressor and or hoses likely has provision for a high pressure cutout switch. If you're running R134a you'll want to add a HPCO switch in series with the LPCO and thermal switches because it has a tendency to run much higher pressures than R12 or HC blends.
I'd use a relay to offload the control amperage to the actual compressor clutch so the high amp load of engaging the electromagnet is run through an easy to replace $1.25 relay rather than the HVAC controls and the LPCO and Thermal switches.

Get a relay socket rather than using 1/4" disconnects. It makes the wiring job look better and it's much easier to replace the relay when and if it needs to be done.
Run a ground in series through the LPCO, HPCO, and Thermal switch to terminal 85 of a Mini ISO Bosch Automotive relay.
Run the Green AC compressor "on" wire from the HVAC control panel to terminal 86 of the same relay.
Run a 14ga wire through a 16ga fusible link or a 20A ATC fuse from the J stud on the firewall to the relay common terminal 30.
Run a 14ga wire from relay terminal 87 (normally open) to the actual compressor clutch plug.